Senior Software Engineer, Agent Platform

About the role

At Klaviyo, we value the unique backgrounds, experiences and perspectives each Klaviyo (we call ourselves Klaviyos) brings to our workplace each and every day. We believe everyone deserves a fair shot at success and appreciate the experiences each person brings beyond the traditional job requirements. If you're a close but not exact match with the description, we hope you'll still consider applying. Want to learn more about life at Klaviyo? Visit klaviyo.com/careers to see how we empower creators to own their own destiny.

As a Senior Software Engineer focused on the Agent Platform, you will help define the technical foundation for how intelligent systems power customer growth. This role operates at the intersection of scalable infrastructure and applied artificial intelligence, where backend performance directly impacts business outcomes. You will contribute to systems that serve as the backbone for AI-driven marketing and engagement solutions used by over 167,000 customers.

This role is hybrid and based in Boston.

What you'll do

You will design and build backend systems to scale AI solutions for 167K+ customers. This includes architecting services that support high-throughput data processing, reliable execution of agent workflows, and secure handling of customer data at scale. You will contribute to our agentic architecture to support performant AI agents, ensuring that backend services meet the demands of real-time and batch processing for enterprise workloads.

You will build tools to tune LLM-based features, deploy agents, implement MCP and RAG patterns in production, and evaluate performance using tools like Arize, OpenAI, Bedrock, LangChain, vLLM and Ray. These tools will enable experimentation, monitoring, and optimization of AI behaviors in production environments. You will develop reliable, scalable data pipelines and APIs for AI systems, ensuring that data quality, latency, and throughput meet strict operational standards.

You will foster a culture of ownership, experimentation, and customer-first thinking across the engineering organization. Collaboration with product managers, ML engineers, and data scientists will be central to delivering real-world impact at scale. You will influence architecture, async processing, and distributed systems decisions for backend-heavy initiatives, helping to define best practices for reliability and maintainability. You will support the deployment and optimization of agent solutions that drive measurable business outcomes, including conversion impact and customer engagement.

Requirements

We encourage candidates to apply even if they do not meet all the qualifications listed. AI Ops is a rapidly evolving space and we are all constantly learning.

You must have 5+ years of experience as a backend software engineer, building scalable, distributed systems. You should bring strong experience working in production environments and launching ML/AI projects in live products. Hands-on experience with generative AI and agentic AI applications in production is essential, along with proficiency in Python (or similar language).

You must be comfortable collaborating with cross-functional technical partners, including product, design, data, and infrastructure teams. Curiosity, proactiveness, and a commitment to continuous learning are required, along with the ability to evaluate and integrate emerging AI and ML tools into production workflows. You should demonstrate commitment to writing reliable, scalable, and maintainable code that can withstand rigorous operational demands.

Nice to have experience with big data tools (e.g., Apache Spark, Ray), familiarity with cloud infrastructure (AWS, Terraform, Kubernetes), and knowledge of ML frameworks (Huggingface, PyTorch, TensorFlow, Keras).

Practical notes

This role is hybrid and based in Boston. We use Covey as part of our hiring and / or promotional process. For jobs or candidates in NYC, certain features may qualify it as an AEDT. As part of the evaluation process we provide Covey with job requirements and candidate submitted applications. We began using Covey Scout for Inbound on April 3, 2025.

Compensation and pay transparency

We pay competitively and reward outstanding performance. Salary ranges are based on role, level, location, and candidate experience. Pay may vary within the range based on these and other factors. Candidates located in the United States of America will be paid within the USD ranges published in this job description.